Butterfly Wings and Nuclear Disasters

The news keeps getting worse at Japan’s Fukushima Daiichi nuclear power plant, with the AP now reporting that the fuel rods in all three of the stricken facility’s reactors are experiencing partial meltdown. In one of the reactors, the level of cooling water has fallen effectively to zero, leaving the fuel rods fully exposed.

One of the questions raised by all of this — a question that can better be answered, surely, after the initial crisis has passed — is how this could have happened in Japan, an island nation sitting atop four tectonic fault lines that knows better than any place on Earth the mess you can get into when you mix earthquakes, tsunamis and nuclear power. Japanese engineers and public safety officials have been rightly praised this week both for their earthquake resistant infrastructure and their smoothly running emergency procedures. So how could the technology have gone so enormously awry? The answer is that nothing big went wrong at all — but a lot of small things did.

The crisis at Daiichi is principally a result of flooding, which inundated the plant’s emergency power systems and made it impossible to pump needed cooling water to the fuel rods. Paradoxically, too much water where you didn’t want it resulted in too little where you need it.

That was a foreseeable result of a tsunami, which was a foreseeable result of an earthquake, so why didn’t the Japanese prepare? They did, building a seawall near the plant that was supposed to stop the inrushing waves. As we learned in New Orleans in 2005, however, levees can be overtopped and that’s what happened here. Still, simply because the region flooded didn’t mean the deisels had to be swamped. Protecting them properly or situating them above the anticipated waterline could have kept them dry and running. But since the Fukushima designers assumed the seawall would be sufficient, they didn’t consider the diesels at risk, and they thus installed them in the plant’s basement — where they were quickly and disastrously swamped. Everything that has followed at least indirectly flowed from those two oversights.

This is part of what chaos theorists call the butterfly-wing theory — the idea that a butterfly flapping its wings in, say, Beijing, can set off a cascading chain of events that eventually lead to a hurricane in, say, the Bahamas. It’s also a premise that both military and commercial test pilots are taught from the moment they step into a cockpit. It’s not a sudden, massive breakdown that is likeliest to kill them — an engine blowing up or a wing dropping off. Rather, you’ll be done in by a series of tiny, unlucky accidents — a blown fuse which leads to a faulty gauge which leads to a clogged fuel line being overlooked, which leads, after several more such causative links, to a very big and tragic effect.

The Fukushima plant has not reached that end stage yet. And no matter how things turn out, it’s likely that future plants will likely be built behind higher seawalls, with better-protected generators. The job now is to break the next link in the current crisis — before it can lead to all the ones that follow.